MARION — As Tabor Academy held its first-ever Tuesday graduation under a tent, Boston Marathon race director Dave McGillivray told the Class of 2014, "Do what you love and make a difference."

McGillivray, who has run more than 130 marathons and participated in eight triathlons, spoke of "every day being a gift" and the importance of finding something you're passionate about.

He said he ran his first Boston Marathon in 1973 as a senior in high school, but didn't finish the race. The same thing happened the next year but on his third try he completed the marathon. He said he was inspired by his late grandfather whose grave McGillivray passes during the race.

Now 60, he has run in every marathon since. "I just want to keep going, and going, and going."

The boys wore red, white and blue, the girls wore white dresses and carried red roses as close to 140 graduating seniors heard his words from under a tent on the Tabor waterfront.

"Today we find ourselves in a new day and time," said Head of School John Quirk. "It is incredible to be seeing it with all of you."

Prior ceremonies have been held on Saturdays but presiding over his second graduating class on Tuesday, Quirk noted to students, parents, and faculty that long-time instructor G. Bruce Cobbold, president of the Tabor chapter of the Cum Laude Society, is retiring after 48 years of service at Tabor.

"We will miss him dearly," said Quirk, with the audience applauding as Cobbold stood on stage.

Quirk also acknowledged the parents in the audience. "This is a day to celebrate the accomplishments of your children." He then asked members of the Class of 2014 to rise from their chairs and recognize their parents.

"They are responsible for this day. Tabor's greatness resides in you," he said.

Senior McKinley Halpern-Reiss, student head of the school, told fellow graduates that "Tabor has changed me to who I am today. We are leaving behind a way of life. We are family."

In part, they will carry with them advice from McGillivray who urged them, "Just do something meaningful as you are the most important person under this tent."